Persons confined to a wheelchair are often faced with a difficult task of having to move themselves to and from a raised bed of a vehicle. Numerous lifting devices have been developed to assist handicapped individuals to transport themselves to and from a vehicle without requiring the assistance of another person. The following patents relate to such lifting devices known in the prior art: Tauer (U.S. Pat. No. 3,826,386; issued July 30, 1974); Deacon (U.S. Pat. No. 3,913,759; issued Oct. 21, 1975); Deacon (U.S. Pat. No. Re. 31,178; issued Mar. 15, 1983); Hock (U.S. Pat. No. 4,252,491; issued Feb. 24, 1981); Couture (U.S. Pat. No. 4,265,586; issued May 5, 1981); Dudynskyj (U.S. Pat. No. 4,285,416; issued Aug. 25, 1981); Kingston (U.S. Pat. No. 4,347,030; issued Aug. 31, 1982); and Pohl (U.S. Pat. No. Re. 30,462; issued Dec. 30, 1980). Most of these references disclose lifts which are mounted near a door opening of a van-type vehicle. The lift platforms are often hinged to enable the platforms to be folded into an upright position within the vehicle when not in use.
Rohrs et al. (U.S. Pat. No. 4,124,130; issued Nov. 7, 1978) discloses a safety barrier for a wheelchair lift.
Safety, stability, and ease of operation are of primary concern in the design of a lifting device. The devices known in the prior art have been only partially successful in meeting these objectives and have been relatively bulky, complex in construction, expensive to fabricate and install, and have been subject to breakdown and tampering. Safety barriers to prevent the wheelchair and its occupant from falling off of the lift, either off of the outer edge of the lift and/or down through the gap between the inner edge of the lift and the vehicle, have either not been provided or have been less effective than those found in the present invention. Exposed chains and linkages of the prior art present not only a source of annoyance, wherein the operator or occupants of the vehicle may contact such elements and become soiled, but also present a major safety hazard if contacted during the operation of the lift. Many of the previously known lift devices also have a tendency to sway, rotate, jump, or bind as the lift is being operated.
The Applicant and his attorneys believe the listed patents taken alone or in combination neither anticipate nor render obvious the present invention. The citations do not constitute an admission that such references are relevant or material to the present claims. The above cited references only relate to the general field of the disclosure, and are cited as constituting the closest art of which the Applicant and his attorneys are aware. None of such references incorporate the combination of features taught in the present invention. Nor do such previously known devices incorporate the same degree of safety as found in the present invention.